1. Field of the Invention
The present invention concerns a patient bed for reproducibly positioning and supporting a patient in a medical diagnosis or therapy apparatus, preferably in a CT apparatus or in an MRI apparatus (magnetic resonance imaging apparatus), of the type wherein the patient bed supports at least some regions of the patient body in a desired position and at least one positioning means enables positioning of the regions of the body with regard to the patient bed.
The invention also concerns a method for reproducibly positioning and supporting a patient in a medical diagnosis or therapy apparatus, preferably in a CT apparatus or in an MRI apparatus, wherein at least some regions of the patient body are supported in a desired position, and wherein at least some regions of the patient body are positioned with regard to the patient bed.
2. Description of the Prior Art
In various medical applications, it is necessary to support and position a patient exactly as he or she was supported and positioned in a preceding examination or treatment. For example, in radiation therapy that follows a computed tomography examination, it is particularly important that the patient be supported and positioned precisely as he or she was supported and positioned in the preceding computed tomography examination. Various special supporting and positioning aids are used for this purpose.
One such positioning aid described in European Application 03004035, the teachings of which are incorporated herein by reference. A method and a device for repeated precise relative positioning of a patient are specified in this document. In this method and with this device, a first reference position of a patient is acquired with two cameras that preferably image the patient from two independent planes. If the patient should again be brought into the original first position, the current position of the patient is reacquired by the cameras and compared with the exposures of the first reference position. The current position of the patients is modified until the camera images of the current position coincide with the camera images of the first reference position. A repeated and very precise positioning of a patient is thereby enabled. However, it is sometimes possible that this desired therapy or examination position of the patient is not comfortable for the patient and therefore cannot be maintained over a longer time span. In order to support the position of a patient or to be able to approximately fix the posture of the patient, various supporting aids are known.
The following supporting aids have previously been used dependent on the body parts of the patient. Skull shells or face masks are attached on the head of the patient for fixing of the head. Specially-formed pads are used for the abdomen. The achievable reproducibility in the repositioning is in the range of a precision of several millimeters to several centimeters. Moreover, these known supporting aids are for the most part considered to be unpleasant and uncomfortable by the patient. Products known as a vacuum mattresses would also be suitable for comfortably maintaining the patient in a fixed position. These are plastic shells that are filled with polystyrene pellets. Upon placement of a patient therein, however, such mattresses can initially shift against one another and, due to body weight, the patient sinks somewhat into the mattress; the air is then suctioned from the plastic shell. When the negative pressure is then taken away again, the mattress loses its shape. In order to keep the shape reproducible, a vacuum mattress must be stored with maintained vacuum for ever patient. In radiation therapy clinics, many hundreds of patients are simultaneously in treatment at a specific point in time, such that this practice is impractical.
For examinations and treatments of the body or body parts, it would be desirable to be able to reproducibly support or fix the patient or parts of the patient's body during the examination or treatment without giving the patient a claustrophobic feeling. Moreover, the examination or fixing of the body part or of the entire body should ensue such that the position can be maintained over a longer time span without the patient developing symptoms of fatigue.